cast/streaming/receiver_message.h

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CAST_STREAMING_RECEIVER_MESSAGE_H_
#define CAST_STREAMING_RECEIVER_MESSAGE_H_

#include <memory>
#include <string>
#include <vector>

#include "absl/types/variant.h"
#include "cast/streaming/answer_messages.h"
#include "json/value.h"
#include "util/osp_logging.h"

namespace openscreen {
namespace cast {

enum class MediaCapability {
  kAudio,
  kAac,
  kOpus,
  kVideo,
  k4k,
  kH264,
  kVp8,
  kVp9,
  kHevc,
  kAv1
};

struct ReceiverCapability {
  static constexpr int kRemotingVersionUnknown = -1;

  Json::Value ToJson() const;
  static ErrorOr<ReceiverCapability> Parse(const Json::Value& value);

  // The remoting version that the receiver uses.
  int remoting_version = kRemotingVersionUnknown;

  // Set of capabilities (e.g., ac3, 4k, hevc, vp9, dolby_vision, etc.).
  std::vector<MediaCapability> media_capabilities;
};

struct ReceiverError {
  Json::Value ToJson() const;
  static ErrorOr<ReceiverError> Parse(const Json::Value& value);

  // Error code.
  // TODO(issuetracker.google.com/184766188): Error codes should be well
  // defined.
  int32_t code = -1;

  // Error description.
  std::string description;
};

struct ReceiverMessage {
 public:
  // Receiver response message type.
  enum class Type {
    // Unknown message type.
    kUnknown,

    // Response to OFFER message.
    kAnswer,

    // Response to GET_CAPABILITIES message.
    kCapabilitiesResponse,

    // Rpc binary messages. The payload is base64-encoded.
    kRpc,
  };

  static ErrorOr<ReceiverMessage> Parse(const Json::Value& value);
  ErrorOr<Json::Value> ToJson() const;

  Type type = Type::kUnknown;

  int32_t sequence_number = -1;

  bool valid = false;

  absl::variant<absl::monostate,
                Answer,
                std::vector<uint8_t>,  // Binary-encoded RPC message.
                ReceiverCapability,
                ReceiverError>
      body;
};

}  // namespace cast
}  // namespace openscreen

#endif  // CAST_STREAMING_RECEIVER_MESSAGE_H_